The so called blade coating technique is a prior art method for the coating of running webs. This technique that exists in lots of varieties is based on the principle that a coating medium (colour, starch for example) surplus is supplied at a surplus to the web at a position prior to a final dosing metering means. Said final dosing and metering means may be composed of structure combined with thin flexible blades, rigid blades or rods that, similar to puttying, doses out and applies the amount of coating medium, see for example WO 2007/061378 which is herewith incorporated by reference. The dosing and coating means are comprised in an applicator arrangement, which for instance comprises means for handling the surplus of the coating medium, which is returned for circulation and reuse by the arrangement. Prior art applicator arrangements present several disadvantages, e.g. having a bulky and relatively complex structure.
In US 2001/0008118 a coating device for directly or indirectly applying a coating medium onto a running paper- or boardweb is shown. The device includes nozzle lips of which at least one is being formed by a blade element. By applying an elastic nozzle lip, the nozzle gap can be enlarged. The coating device includes a mechanism for adjusting the height of the nozzle gap. A disadvantage with this design is that it designed as a separate unit implying difficulties in achieving a compact design of the whole application arrangement.
A related problem within the field of dosing and coating arrangements is that the coating medium mostly has to be supplied at a temperature that is different (normally higher) compared to ambient temperature, in combination with the fact that the total applicator arrangement is relatively large, i.e. extends over the cross machine width. As consequence there may result temperature gradients causing bending of the applicator arrangement, which may result in coat weight variations. According to prior art this problem is commonly handled by costly and bulky temperature control structures, e.g. as shown in EP 0 931 878. This prior art document describes a fountain coating applicator presenting an alternative manner of handling the latter problem, i.e. the tendency of heated coating to cause a temperature gradient is counteracted by cantilevering the applicator head on arms from a support beam through which a temperature-controlling fluid is circulated.